Knitting machines

ABSTRACT

In a knitting machine a cam formed with an edge profile comprising the locus of a plurality of points related to the operation of the machine and joined by a fourth degree curved and having tangential line portions adjacent some of the points producing zero acceleration.

O Unlted States Patent [151 3 673 81 s Havranek et al. 1 July 4, 1972 [5 KNITTING MACHINES Reference-S Cited [72] Inventors: Milan Havranek, Brno; Drahomir Zouhar, UNITED STATES PATENTS Blansko; Josef Dusik, Trebic; Jaromir Ku- 1120,423 6/1937 Robaczynski ..66/78 X cera, Trebie; Jiri Krejcirik, Trebic, all of 586,315 7/ MlmSil'lg X Czechoslovakia 3,173,277 3/1965 Fregeolle ....66/107 u 3,192,742 7/1965 Haddad ..66/57 mex'ldfvody J F 3,421,344 1 H969 Moyer et al ..66/57 x generalnl reditelstvi, Liberec, Czechoslovakia FOREIGN PATENTS OR APPLICATIONS [22] Filed: Sept. 29, 1969 941,564 4/1956 Germany ..66/57 368 76 3 1932 G tB 't ..66 57 21 App]. No.1 861,816

Primary Examiner-Wm. Carter Reynolds 3 Foreign Application Priority Data At10meyRichard Low and Murray Schaffer Oct. 2, 1968 Czechoslovakia ..6823/68 [57] ABSTRACT v In a knitting machine a cam formed with an edge profile comprising the locus of a plurality of points related to the opera- 58] Fie'm 107 08 tion of the machine and joined by a fourth degree curved and having tangential line portions adjacent some of the points producing zero acceleration.

1 Claim, 4 Drawing Figures PATENTEDJUL 4 I972 sum 1 or 2 mu HAVRMEK DRAHOMIR zouHnR JOSEF swam JA oMm KvcERfl d IR! KREO'CIRI K INVENTORS KNITTING MACHINES BACKGROUND OF INVENTION The present invention relates to a circular knitting machine, and particularly means for mounting control butts and cams.

As is well known, the needle cylinder of a circular knitting machine is provided with needle grooves in which the needles are traversably mounted, the needles being controlled during the knitting process either by their own control butts and/or by separate control means such as jacks, intermediate sinkers, and similar elements, which are themselves provided with control butts. The butts are guided in a cam housing of a conventional stationary and/or movable cam system.

In prior art constructions, no special care was taken to accurately construct the guiding edges of respective cams, and as a result of which undue mechanical stressing of the controlled butt elements occurred. This posed little problems when the control butts were not operated at high speeds, however, with more modern techniques increasing, the efliciency and speed of the knitting machines, this now poses a considerable problem. The presently known constructions of the cams are imperfect and these cams cannot withstand the increased speed and load placed on them.

It is an object of this invention to provide cam structures.

It is another object of this invention to provide cam struc tures removing the disadvantages mentioned above.

It is another object of this invention to provide cam structures able to double or triple the speed at which the control butts are operated without causing damage to the needles, or to the knitwork, or cause undesired yarn breakage. It is a specific object of the present invention to provide a cam structure for knitting machines which provide increased efficiency and speed in operation. 7

According to the present invention, there is provided in a knitting machine having lift cams and kinking cams, at least a series of continuous curves connectinG a plurality of oints related to the operation of the machine. Some of these curves are of the fourth degree. Tangents occur at each of the points. Needles pass through zero acceleration at some of these points.

In particular in one form of the invention the tangential line at the selected points forms with a line, parallel to the plane of the cam, an angle of and within predetermined ranges and limits.

DESCRIPTION OF THE DRAWINGS With this particular construction, the various advantages noted above are effected. These advantages, as well as other, together with an example of the practical embodiment of the present invention is disclosed herein and in the accompanying drawings, of which:

FIG. 1 shows a diagrammatical front elevation view of the main part of the cam system in developed form and when looking from the center of rotation of the needle cylinder,

FIG. 2 a partial front elevation view of the kinking cam of the main knitting system in enlarged scale,

FIG. 3 a detailed side view of the upper part of the latch needle at the moment, at which after introducing the yarn the closing of the needle hook by the latch begins, and

FIG. 4 the same view as shown in FIG. 3 with the difference, that a position is shown corresponding to the terminating point of closing the hook of the needle by means of a latch.

DESCRIPTION OF THE INVENTION Turning to the figures, the conventional one cylinder, two feed, circular knitting machine is provided in its upper part with a needle cylinder having two knitting systems I and 11 (FIG. 1). These knitting systems I and II comprise the feeding of one or more yarns Y arranged beside each other (FIG. 3). The yarn may be guided by any one of a variety of conventional guides or feed which can be arranged either stationarily or, movubly. In the upper part of the needle cylinder (i.e.from

its outer side) a guiding ring 1 (FIG. 1) is arranged and is provided at the points of the separate knitting systems I and II, respectively, with notches for the noted yarn Y.

The knitting needles 2 (FIG. 3) are traversably mounted in the needle grooves which are themselves mounted longitudinally in the needle cylinder. The said knitting needles 2 are provided in their upper part with hooks 3 and cooperate with latches 4 which are mounted on the pivots 5. In the longitudinal needle grooves, of the rotatably mounted needle cylinder, further control means are mounted adjacent the said knitting needles 2, as for example control jacks, selectors and similar elements which control the needles 2 for the purpose of patterning or other known purposes.

The bottom ends of the knitting needles 2 are provided with control butts 6 (FIG. 1), which operate in the course of passage through the cam system of the knitting machine in the direction of the arrow P. The knitting machine is moved in that direction P as a consequence of the rotary motion of the needle cylinder. The butts 6 are controlled by the separate cams i.e.: the lifting cam 7, the heel cam 8, the main kinking cam 9, of the knitting system 1, the equalizing cam 10, the stationary cam ring 11, two lifting cams 12, 13 the kinking cam 14 of the knitting system II and a further equalizing cam 15.

The jacks, intermediate sinkers, patterning sinkers, various selectors and similar elements of the needle control means have an analogous arrangement arrangement or shape, as the already mentioned stationary or movable cams. Last but not least, it should be noted, that in a similar way the cam system of the apparatus headpiece or cylinder should be constructed, so that conventional transferring keys for transferring the loops when knitting the so-called welt of the stockings can also be effected. The reason for this consists in that the transferring keys are also controlled by the control butts, which move along a path limited by the cam elements mounted in the cam headpiece of the apparatus.

The present invention is directed to the formation of the edge profile of the cams 7-15, to effect the desired end advantages. It is specifically illustrated in FIGS. 1 and 2 in connection with the kinking cam 9, however, it will be understood that similar principles are applicable in the formation of each of the other cams.

In forming the edge profile of each of the cams, in accordance with the present invention, the edge face is produced as a locus of points connected by a series of continuous curves, particularly having a plurality of fixed and predeterminedpoints representing various operational positions of the knitting machine. As seen in FIG. 2 the cam 9 has an edge face on which a plurality of fixed points A to G are located. Each of the curves from points c to B and E to D lie along a fourth degree curve, otherwise referred to as a quartic or biquadratic curve, and may be expressed by the equation ax bx +x=y where a and b are constants, x is an independent variable and y is a dependent variable. The curves from points B to A and D to C each lies along a fourth degree curve which is the mirror image of a.x4-i-bx*lx=y The points A to G are each spaced a distance S from a line p, which represents the theoretical plane in which the cams 7-15 are located. The plane represented by the line p is of course normal to the axis of rotation of the needle cylinder. The location of each of the points A to G is determined by its operation in forming individual loops Y Y in the course of knitting. For example, point A is at the place where the butt 6 initially engages the cam 9, point B is at the point where the hook 3 is initially closed etc.

The curve A-G is generated by assigning predetermined values to the angles [3 formed at each of the points A to G. Each of the angles [3 is taken between a line parallel to the theoretical line p and a tangent to the curve at the corresponding point. Still further, the connecting line between successive points B to C to D, is to be so formed that at the start or end of the connecting lines tangential line portions are formed where there is no, or zero acceleration, (or slope in the face) of the motion of the control butts 6. It is preferred that each of the angles B lies within a respective predetermined range in which at least points B, C, and D generate zero acceleration. As a result of this construction there has been obtained a high degree of emciency and operation not found in the prior art structures.

With this in mind, FIG. 2 can be viewed as showing the exemplary kinking cam 9 as having a point A representing the initial point of impact between the butts 6 and the active edge of the control cam 9, (or any of the other cams 7-15). An angle 3 is fonned between the edge and a line parallel to the theoretical line p which, in accordance with the present invention, preferably lies within the range of 15 to 25.

The point B which represents the initial closing of the hooks 3 of needles 2 by the latches 4 is situated at such a point at whichthe needle 2 is in a laying position, i.e. at which the yarn Y is laid by the separate yarn guides in the separate knitting systems I and II into the hooks 3. Such a position is shown in FlG.3. To the initial point B of closing the hooks 3 of needles 2 by latches 4, an angle B, assigned, ranging from 43 to 53, the parallel side limiting the angle 5,, having a distance S, from the horizontal straight line p, the other side of the angle being tangent to the slope of the curve A-Gat the point B.

The point C representative of terminating the closing of the hooks 3 of needles 2 by latches 4 is determined by the point, at which the latch 4 closed the hook 3 of needles 2 and thus simultaneously enclosing yarn y into the space of hook 3. The position of the needles at that point is shown in FIG. 4. To the said point C, an angle B is assigned, ranging from 20 to 30.

' The point D, representing the point at which the needle loop is formed from the yarn y, is provided with the angle [3 which ranges from 48 to 56. At that point, an increased traction force of the yarn y is exerted on the hook 3 of the needles 2 and the loop y fastened on the needle 2 before it, takes up a position on the latch 4.

The point E, at which the loop forming from the yarn y is terminated, is provided with an angle B ranging from 15 to 25. At that said point E, the loop y, has left the latch 4 of needle 2 and has thus been finally finished.

The point F, at which the kinking of the needles 2 is terminated, is provided with an angle BF Franging from to 8. At that point, the hook 3 of the needles 2 is stressed mostly by the needle loop formed of yarn y. The sides of angle [3 are each defined similarly to that of angle B At last point G, at which the reversing of the movement of needles 2 takes place, is also provided with an angle [3 ranging from 28 to 38. That means, that at this point the needles 2 are moved reversely to the direction of movement about the active edge provided with points A to E. The sides of the angle [3 is defined similarly to angle 3,.

It has also been found as a concomitant of the present invention that in certain applications it is preferable that the lifting cams 7, 10, ll, l2, l3 and 15 be mirror images of the kinking cams 8, 9, and 14. This presents no problem since either of the cams may be generated from left to right or right to left as shown in FIGS. 1 and 2, and applied in the conventional machine.

Other than the preferred angular ranges noted above it has been found that a variety of angles B may be generated and still maintain the present advantages. The angles may be made in a number of tolerances and may deviate from the range suggested by upwards of plus or minus 5 to 10. The ranges given previously being only preferable and illustrative. As an example of the various modifications, the angle B, at the point B at which the closing of the hooks 3 may be as low in value as 42 1 1. As other examples, at the point A of impact of the control butts 6 against the active edge of the cams 7 to 15, the angle B may range from 30 1- 5, the angle fi at point D at which begins the loop forming of the laid yarn y of middle length, ranging from 45 3, the angle [9 at point E, i.e. at the point at which the loop of yarn y is finished, ranges from 40 to 45 and finally the angle 3; at the point F at which the kinking of the control butts 6 of needles 2 is finished, ranges from 30 1 5. At this combination it is advantageous, when between the point A of unpact of the control butts 6 against the active edge of the cam and the point D, at which the loop fomiing of the yarn y begins, the points B and C are replaced by a tangent having an angle of 39 1 3, this inclination being determined in view of the horizontally arranged straight line p.

It will thus be seen that the construction of a cam profile in accordance with the present invention is quite simple and may easily be effected. Knitting machines so provided have functioned well and successfully.

What is claimed is:

1. In a circular knitting machine provided with knitting needles having butts guided by a cam system controlling the speed and direction of movement of said needles, a cam comprising an edge profile having a face formed by a series of continuous curves connecting a plurality of points, each related to the moving of the needles during knitting operation, said plurality of points representing respectively a first position relative to the impact of said butts on said cam, a second position relative to the initiation of the closing of the needle hooks, a third position relative to the termination of the hook closing, a fourth position relative to the formation of the loop, a fifth position relative to the finishing of the loop, a sixth position relative to the finishing of the kinking and a seventh position relative to the reversal of motion of the butts, said first and second, second and third, third and fourth, and fourth and fifth pairs of points, respectively, being connected by a fourth degree curve, a tangent to the said continuous curves occuring at each of said plurality of points, said tangent occuring at each of said points forms an angle with a line parallel to the theoretical plane of said cam, the angle corresponding to the first point being between 15 to 25, the angle at the second point being between 43 to 53, the angle at the third point being between 20 to 30, the angle at the fourth point being between 48 to 56, the angle at the fifth point being between 15 to 25, the angle at the sixth point being between 0 to 8, and the angle at the seventh point being between 28 to 38, said points generating a condition of zero acceleration of the motion of said needles at at least the second, third and fourth positions. 

1. In a circular knitting machine provided with knitting needles having butts guided by a cam system controlling the speed and direction of movement of said needles, a cam comprising an edge profile having a face formed by a series of continuous curves connecting a plurality of points, each related to the moving of the needles during knitting operation, said plurality of points representing respectively a first position relative to the impact of said butts on said cam, a second position relative to the initiation of the closing of the needle hooks, a third position relative to the termination of the hook closing, a fourth position relative to the formation of the loop, a fifth position relative to the finishing of the loop, a sixth position relative to the finishing of the kinking and a seventh position relative to the reversal of motion of the butts, said first and second, second and third, third and fourth, and fourth and fifth pairs of points, respectively, being connected by a fourth degree curve, a tangent to The said continuous curves occuring at each of said plurality of points, said tangent occuring at each of said points forms an angle with a line parallel to the theoretical plane of said cam, the angle corresponding to the first point being between 15* to 25*, the angle at the second point being between 43* to 53*, the angle at the third point being between 20* to 30*, the angle at the fourth point being between 48* to 56*, the angle at the fifth point being between 15* to 25*, the angle at the sixth point being between 0* to 8*, and the angle at the seventh point being between 28* to 38*, said points generating a condition of zero acceleration of the motion of said needles at at least the second, third and fourth positions. 